Fuel calorimeter



De. 31, 1935. R, w KEn-H i v2,026,180

FUEL yCALORIMETER Filed Nov, 29, 1955 2 Sheets-Sheet 1 34/ [13A 2LH35 ze [13B f7 HA "m $2 ging y @at 23 25 40A 42A 42B- 40B 22A 1 '-24 1oA/\ I A l /lo 16A 20A 12 #205 les HA `30A am? "1% 30B" -2 g- 27A 273 14B am 3. 28A 28B 327 2'@ ISA A er 2 15B 'A J ZA m Q HA u l i 1 lw i ATTORNEY;

Dec. 31, 1935. R. w. KEITH 2,026,180

FUEL CALORIMETER Filed Nov. 29, 1953 2 Sheets-Sheet 2 f? Y /f y le?.

' F' .2 mano IG \N. DHA

' INVENTOR ,30| V K. BY W F |G.3 I ATTORNEY Patented Dec. 3l, 1935 UNITED STATES eATENT OFFICE 25 Claims.

My invention pertains to a simple, novel calorimeter of the multiple chamber type for continuously determining the caloric value of a combustible, and more particularly relates to structural means for effectively measuring and automatically recording the heating value of a combustible without the need of any liquid as an intermediary cooling agency.

The method of operation that underlies my improved apparatus is primarily based upon an oiset or thermal balance principle in which a gaseous heat absorbing agency containing free oxygen is successively heated in two separate steps at commensurable input rates. One such step brings about a definite temperature rise by burning an unknown combustible in such working fluid to impart a relatively small surplusage ol sensible heat thereto; while the complementary or counterbalancing step may be instigated by means of any adjustable heating medium whose rate of thermal output is definitely known and made capable of selectively inciting a temperature rise that closely corresponds to that of the rst named step. When the temperature rise occurring in each such step is maintained at substantially equal value, a comparative measure is afforded for directly evaluating the rate of heat supplied by the unknown combustible in terms of an equivalent known heating effect. The described order of these successive heating steps may be reversed and still produce an identical result. As a further refinement, my working fluid may also be alternately utilized as a heat absorbing agency and as a cooling medium.

The present instrumentalities are of the continuous iiow calorimeter type, comprising a pair of cooperating primary and secondary combustion chambers which may be kept substantially identical as far as their respective structural and thermal characteristics are concerned and may collectively be termed complementary chambers. One point of structural novelty resides in interconnecting the top of a tubular primary chamber in series with the bottom of a similar secondary chamber by conduit means and conducting a stream of gaseous working fluid therethrough Whose major constituent is atmospheric air. Such conduit means preferably, but not necessarily, includes an interposed compartmental heat exchanger or the like intercooler device.

Broadly considered, a localized body portion of flowing working fiuid may be successively heated in any suitable manner while passing through the respective complementary chambers. In my preferred embodiment, each of these multiple combustion chambers may be equipt with a separate test burner, of which one such may be supplied from a source of standardized combustible of known heating value While the other burner is fed with sample gas of unknown heating value, the rates of fuel supply to the respective burners being made relatively adjustable and quantitatively determinable by appropriate control means. Prior to reaching the primary chamber, a stream of fresh working fluid may initially be passed through one compartment of my heat exchanger in order to preheat such incoming air stream to a limited extent and thereby obviate moisture condensation during the subsequent cooling thereof. No correction is then needed to take account of such condensation, my calorimeter being preferably arranged to register the net or lower heating value of the sample gas.

A relatively large volume or stream of preheated working fluid is made to flow steadily into the primary combustion chamber that shelters the test llame whose gas heating value is to be determined. Since a comparatively small volume of sample gas is intended to be burned in the presence of a large excess of preheated air, the rate of sensible heat input is inherently limited, which in turn correspondingly restricts the resulting temperature rise. Such flame heated working fluid may then be cooled by conveying the same from the primary combustion chamber through a different intercooler compartment and placing the conveyed ilud in heat exchanging relationship with the current of fresh air that is simultaneously fed through the rst cited intercooler compartment. After leaving the primary chamber, said fluid stream may be reduced to the same temperature that prevails in the preheated air being entered into the primary combustion chamber. Thereupon the working fluid may be delivered into the secondary combustion chamber and reheated therein at a measurable rate of input by the use of a small standardized reference flame or an equivalent supplemental heating means. The respective rates of gas flow to the test flame and to the reference flame may be manually adjusted or automatically manipulated so that the temperature rise in both combustion chambers is maintained in a substantially equal relationship. It is pointed out that in my improved calorimeter, one and the same working iiuid is successively and cooperatively passed through both complementary combustion chambers and reheated in one such chamber.

Sensitive temperature responsive devices may be arranged in both the primary and secondary combustion chambers in order to determine when the desired temperature conditions have been achieved. By starting the cited reheating operation in the secondary chamber from the same temperature level that initially prevailed prior to entering the primary chamber, a similarity of temperature condition is realized, with the result that the mean specific heat of the working uid as well as the calorimeter heat losses become substantially equalzed. My calorimeter is however capable of rendering reasonably exact determinations without resort to any intercooler and still provide for an instrument whose inherent inaccuracy remains negligible in meeting the more practical requirements.

Instead of adjustably altering the proportionate supply of combustible gases delivered to their respective flames, the gas of unknown heating value and the standard reference gas may as an alternative, be supplied to their respective test burners in a volumetric fixed ratio, `whereupon the resulting successive temperature risesv that occur in the respective combustion chambers, may likewise be used as a comparative measure of relative heating values when a definite rate of uid flow is maintained therethrough.

My copending prior application, Serial No. 477,888 as filed August 26, 1930, is descriptive of a method and apparatus that in certain respects is analogous in its teachings to the foregoing, the instant disclosure being a continuation in part thereof.

The object of the present invention is to: provide for certain refinements in method and structural aspects over said original application and to otherwise improve the performance thereof, by working with calorimeter means possessing the previously described characteristics and capable of accurately determining the thermal value of a combustible without need of computing allowances for heat losses, room temperature or humidity of the air supply.

A further object is to equip said apparatus with certain control appurtenances and adapt the same to function cooperatively with differential recording devices designed to automatically regulate the gas supply to my multiple calorimeter; also to provide facilities for at times, checking the readings obtained and to permit of making adjustments that will insure a high standard of performance on the part of said instrument. Other features of improvement will hereinafter be more explicitly pointed out.

Reference is had to th'J accompanying two sheets of drawings which are illustrative of certain preferredV structural arrangements of my invention, and in which drawings:

Fig. 1 cross-sectionally represents a schematic elevational view through the principal parts of a fuel calorimeter assembly embodying my invention as equipt with automatic control devices.

Fig. 2 is a view similar to Fig. 1 but discloses certain modifications of the recording mechanism and mode of manipulation.

Fig. 3 diagrammatically depicts certain alternative details pertaining to a substitute reheating coil.

Referring more specifically to the drawings, attention will rst be directed to the Fig. 1 style of instrument. In this upright calorimeter embodiment, there are provided two laterally spaced primary and secondary combustion chambers respectively designated their entirety as' IElA and IUB, which may respectively be heat insulated in a suitable manner to minimize heat losses.

The structure of each such component chamber is intended to be substantially alike and to possess other similar inherent characteristics. The reference numerals indicating the various housing parts will be followed by the letter A to designate primary chamber members and by the letter B when referring to the secondary chamber.

The tubular insulated jackets IIA and IIB of these complementary combustion chambers may at their bottom regions, respectively be provided with a laterally disposed intake port or passageway I2A and IZB, while each upper region thereof respectively communicates with the discharge port or passageway 23A and ISB.

'Ihe open bottom of each such jacket may be closed by a removable cover plate 39A or SESB. Separately mounted thereon are the upstanding jet burners 29A and 29B that respectively terminate in the small test flames ISA and ISB. 'Ihese ames may be ignited by electric pilot means ZIA and 2 IB or the like. Said gas burners are preferably of the premixing type and respectively housed within the tubular draft casings MA and IIIB which protect the flame against direct radiation and extinction. The uppermost end of the respective burner casings is capped. and a plurality of delivery or crown ports ISA and IGB are disposed therebeneath through the casing. A similar seriesof intake or draft ports IEA and IEB are located at the lowermost region of the respective casings.

The respective topmost regions of the tubular jackets IIA and IIB are substantially closed by the annular crown plates 38A and 38B. The innermost perimeter of each such plate respectively carries the depending outlet tube lIIA or MB serving to support the cylindrical mixing boxes @IBA and 40B in elevated relation to the aforesaid crown ports. Said boxes may each be provided with a series of radially opposed mixing apertures 42A and 42B. 'Ihese apertures are arranged to project the incoming working fluid inwardly into impinging relationship and thence upwardly through a single discharge outlet so as to promote turbulence which thus brings about a substantially equalized temperature throughout the respective flowing fluid bodies prior to leaving their mixing boxes through the contracted tubes thereof. Y

For heat insulating purposes, each jack wall such as IIA and IIB, may respectively be equipt with an interiorly spaced lining tube 22A or 22B to constitute therebetween a hermetically sealed vacuum chamber such as 36A or SBB. The

effectiveness thereof may be augmented by in- 1 teriorly applying a silvered coating to the respective chamber walls.

AS a further precautionary measure against heat loss, the delivery end of the intake passageways IZA and IZB may respectively be commanded by the antiradiation shields 21A and 21B, which each preferably comprises a plurality of cross-sectionally channel shaped metal slats or baiiles that are stacked in superimposed gratelike relation and adapted to divert the gaseous flow therethrough in zigzag fashion. Spacedly located ahead of each such shield, is a perforated grid 28A or 23B intended to effect a well distributed flow into and through their respective intake passageways.

The various channels leading through my combustion chambers are so interconnected that a major portion or main current of working fluid entering the passageways I2A and I2B, will now upwardly around their respective burner casings I 4A and I4B while a minor portion feeds through the draft ports I5A or I5B and out of the crown ports IBA or I 6B. After being combined, each such stream of working fluid is thereupon fed upwardly within the confines of the lining tube and thence into a mixing box for delivery into the respective discharge passageways such as ISA or I 3B, said course being represented by arrows.

A crossfeed conduit unrestrictedly interconnects the discharge passageway I3A with the intake passageway I2B. Inbuilt around such connective conduit is shown a compartmental heat exchanger 22 comprising the tubular shell 23 of which the respective ends may be enclosed by a header 24; between these headers there extends a bank of intercooler tubes 25 of which the interior denes one compartment of my intercooler and the surrounding space constitutes another compartrnent thereof. The intercooler shell is further shown equipt with a controllable air feed duct 26 arranged to supply atmospheric or room air around the exterior of the tubes 28. Said fresh air may be delivered downwardly through the primary feed passageway IZA. Similarly, the down coming working iiuid after leaving the intrcooler tubes, may be directed into the secondary intake passageway IZB, which then becomes a component of the chamber interconnecting conduit 25.

As will be understood, independent banks of tubes may also serve for intercooler purposes and these banks may be immersed in a common water bath. In addition, the outlet end I3B of the secondary chamber may be equipt with suitable forced circulating means such as a positively driven draft producing appliance designated as 6l, it being preferred to keep both combustion chambers under a slight vacuum by the use of a suction blower or the like. The total Volume of induced air flow to test flame requirements may be varied within rather wide limits, since the function of my calorimeter is not dependent upon any fixed ratio therebetween.

'Ihe separate fuel supplies required for the burners 2A and 29B are delivered to their respective flames by the gas feed pipes 60A and 6B. The preheater loop sections thereof, namely ZUA and B, may respectively be incorporated within the confines of a different heat exchanger compartment as shown in order that each such combustible may initially be made to closely approach the temperature of the working fluid stream in which it is to be burned.

The respective loop sections may be provided with a bypass valve HA or I'lB as controlled by the needle valve screws I 8A and I8B to admit and respectively regulate the proportion of air that is allowed to mix with the combustible gases prior to reaching their test llames. Only a relatively small amount of working fluid is intended to be bypassed through either valve.

`Respectively mounted within each outlet tube 4IA and 4IB is a temperature responsive device such as 3l or 33, preferably of the thermocouple type. In order that said devices may accurately register the temperature of the gaseous uids being crowded through their respective tubes, the cross-sectional tube area is preferably contracted relative to that of their concentrically mounted boxes 42A. and 42B. Each device may comprise one or more alternately jointed thermocouple units, such for instance as copper and constantan, since these afford a relatively high E. M. F. per degree of temperature difference.

A substantially identical thermometer device presently be more explicitly described. To this 10`- end, a terminal of the thermocouple 3| may be carried to its mated couple 33 by the lead wire 35. A lead wire 3@ extending from the opposite terminal of said mated couple, may be carried to the couple 32, which in turn is connected to the couple 3B by the lead wire 3l. The remaining open terminals of the couples 3i! and 3| are then operatively connected by the leads 3d and 38 to the main control relay 50 whose purpose will subsequently be explained.

Attention will now be directed to my gas pump controls and method for supplying the respective test iiames in an automatically regulatable manner. As previously recited, the primary test burner 29A is supplied with gas through the feed 25-E pipe 60A. The primary fuel metering pump EilA delivers into said feed pipe and draws its supply from a source of gas whose unknown heating value is to be determined by my calorimeter. Such fuel pump is preferably of the positive dis- 30 placement or rotating bucket carrying type capale of accurately measuring the gas delivery at a volumetric rate that shall be directly proportional to the speed of the pump. v

The secondary chamber is shown equipt with 35 separate, corresponding gas handling means including a test burner 29B, a gas feed pipe 6GB and a secondary fuel metering pump BIB which latter draws its supply from a known source of standard reference gas such as hydrogen, acety- 4,0 lene, methane and the like pure combustibles adapted to burn with a substantialy non-luminous flame and whose lower heating value may be predetermined within a close limit. Both of such metering pumps are preferably installed within a 45 common water bath to equalize the temperatures thereof and respectively supplied with gas at the same pressure by suitable regulator means.

My compensating apparatus is centered in an appropriate transmission mechanism for auto- 50 inatically altering the respective speeds of the gas metering pumps relative to each other. In the embodiment diagrammatically depicted in Fig. l, a driven cylindrical drum E35 and a cooperative tapered drum Sli are rotatably mounted 55 in any suitable manner. One end of the drum @il may be gear driven at 53 by the main actuating motor B2, while its other drum end may be extended for direct connection to the secondary gas metering pump SIB which serves the test 60 burner 29B with the stipulated standard reference gas. A shaft end of the driven drum S5 is similarly associated with the primary gas metering pump {EIA that delivers unknown gas to the test burner 29A. A shiftable idler wheel 5l' is shown 65 interposed between said drums and positive adjusting means are provided to fix the operative position of said idler lengthwise of the contiguous drum surfaces in maintained frictional Contact therewith. During any given calorimeter test, 70 the secondary metering pump SEB is preferably run at some fixed predetermined motor speed and by adjustably shifting the idler, the speed of the primary metering pump EIA may be selectively advanced or retarded in relation thereto. It is 75 As shown zol preferred to bring about a one to one speed ratio when the idler approaches the rightward end of its adjustable travel and to correspondingly augment the speed of the primary pump when the idler is moved toward its opposite extreme of travel.

By the proper selection of speed ratios and drum contour, such transmission mechanism can be so designed and calibrated as to make the idler movement directly proportional to a correspondingchange in the lower B. t. u. or net heating value of the unknown gas. The adjusting screw 5e is provided with a carrier 55 which serves to shift the idler Wheel in unison therewith. As indicated in Fig. l, said carrier may also overhangingly mount a stylographic pointer 58 to graphicaly record the test findings upon a suitably indexed chart 59, which latter may be uniformly moved along by coordinated clock or other synchronizing means in a conventional manner.

Referring further to the previously cited relay unit 59, this may be of the galvanometric or potentiometer type of remote control adapted to intermittently start or stop a reversible auxiliary motor 52 as geared to the screw 54 and which relay may be electrically connected to the motor by the lead wires 5I. Certain parts of the potentiometer recorder now being marketed by the Leeds & Northrup Company of Philadelphia, Pa., may be utilized for present purposes.

The minute differential voltage emanating from my thermocouples is sufficient to control such a recorder and to automatically bring about a starting up of the reversible remote control motorV 52 in a fixed direction of rotation dependent upon the direction of effective current flow that may from time to time, be set up within the closed lead wire circuit that interconnects my thermocouples. This auxiliary motor 52 continues to adjust the idler position as long as the thermocouples send forth a current flow through the relay 56. The speed adjustments on part of the drums will automatically cease when the various electric thermometers have been brought into a thermally counterbalanced condition, which in turn shuts down the auxiliary motor. By virtue of the described compensating devices, said idler will however, be promptly shifted into a new vposition in response to any change in the heat value of the unknown gas, and thus continuously register its corresponding prevailing caloric content upon the chart 59.

Having described the more essential structural characteristics of the Fig. l style of calorimeter, its functional mode of operation may now be briey traced as follows:

Assuming both the test flames IBA and ISB to have been lighted and stabilized thermal conditions established, then a steady circulation of the working iiuid will be induced by the blower 6l to flow through the interconnected calorimeter chambers in a path direction indicated by arrows. Fresh atmospheric air is thereby drawn into the feed duct 25 and caried downwardly around the intercooler tubes 25 for delivery through the primary passageway I2A and the shield 21A into the primary combustion chamber IDA. The test flame ESA of itself, imparts slight mobility to the Working fluid, which latter naturally rises because of being intermingled with a relatively small volume of hot combustion products. The calorimeter passages are preferably so proportioned that the addition of burned gas to the desired large excess of air will restrict the total temperature rise to about 50 Fahr. which limit is merely cited as a suitable working basis. Such initially heated working fluid then passes upwardly through the mixing tube 42A and into the contracted end of the outlet tube MA, which brings said initially heated fluid in intimate contact with the thermocouple 3| The other thermocouple 30 is made responsive to the mean intake temperature prevailing in the passageway I2A. These mated couples tend to set up a differential current iiow through their respective interconnecting lead wires that is directly proportional to the dominant temperature difference between such opposed couples.

The heated `working fluid is then conveyed through the interior of the tubes 25 in a heat interchanging relation with the fresh air coming into the feed duct 28 which thereby brings about a preheating of such air current prior to reaching the test burner lsA. It is preferred to so proportion the intercooler that the working fluid upon reaching the secondary passageway IZB, shall be reduced in temperature to a point substantially equal to the temperature prevailing in the primary passageway IZA, in order that the thermocouples 3Q and 32 may be subjected to approximately the same temperature influence.

The intercooled working iiuid is thereupon entered through the intake passageway I2B of the secondary combustion chamber HEB and reheated by the secondary test flame ISB or equivalent supplementary heating means to a point that shall as nearly as possible, correspond to the temperature rise previously imparted by the primary test flame IBA.

After stabilizing or steady flow conditions have been established, the relative supply rates of the sample gas of unknown heating value and that of the standard gas may be effectively regulated by the previously described pump control means, The desired thermal balance may be brought about by resort to a plurality of thermocouples that are preferably interconnected in series with the main control relay unit 58 as described.

The electromotive force generated by the couples 30 and 3l is a function of the existing mean temperature diiference between these two primary chamber regions. In a similar manner, the electromotive force generated between the couples 32 and 33 is dependent upon the temperature rise of the fluid flowing through the secondary chamber. The respective couples of the primary chamber are purposely so connected with those of the secondary chamber that their respective differential electromotive forces oppose one another; hence, when a substantially equal temperature rise occurs in both combustion chambers, the net resulting electromotive force at the lead terminals 3G and 33 will neutralize and equal Zero. On the other hand, should the temperature rise in one chamber become larger than the other, this will generate a proportionate electromotive force whose polarity or direction will depend upon which of the two chambers is subjected to a higher temperature rise. The delicate relay Ell responds to such electrical stimulation and starts the auxiliary motor 52 in a proper direction. The idler 5l is thereupon shifted into a new position of adjustment, the

' control arrangement being such as to automatically regulate and thereby maintain an equalized temperature rise within the respective combustion chambers. Like results may be obtained by the use of a special Wheatstone bridge circuit that is more fully described in my prior application, Serial No. 477,888.

When'by suitable means, the temperature of the fluid going into the primary passageway I2A is kept substantially identical with that entering the second ary passageway I 2B,the thermocouples 30 and 32 may be dispensed with, since the desired thermal balance would be detected by use of the couples 3! and 33 alone. It is pointed outl that regardiess of the type or nature of the temperature sensitive device that may be employed, its purpose as herein contemplated. is notto actually measure a particular temperature nor eve'n a given rise in temperature, but rather to automatically actuate a suitable temperature responsive device capable of bringing about an equality of temperature rise in the same working fluid weight that successively flows through the component chambers of my calorimeter irrespective of the use of any intermediary cooling means.

Owing to the accretion imparted by the slight addition of consumed gas, the weight of the discharged working fluid is slightly in excess of the fresh air originally fed into the duct 26. Since the weight of gas burned is insignificant relative to the amount of total air passed through my calorimeter, the resulting error is a negligible one.

By intercooling the working fluid before undertaking to reheat the same, the radiation and internal conduction losses in the primary .and seccndary calorimeters are substantially balanced and made to neutralize each other.

Furthermore, no correction becomes necessary for a change in average specific heat of the working fluid, which might otherwise need to be taken into accountin the event the multiple calorimeters were operated at an unlike temperature range of considerable magnitude. The cited preheating step also prevents moisture condensation even when the air entering section 26 Vis saturated with humidity. It will be observed that my instrument is also self-compensating as regards any barometric pressure change because both combustion chambers are kept identical in this respect.

As a further precaution against inaccurate temperature registrations, the imperforate crown plates lying directly over each test flame, protectl the overlying thermocouple against direct radiant heat. The shield such as Z'IA serves a like purpose with respect to the mated thermostat 3D. My improved radiation shield absorbs the impinging heat rays and converts such rays into sensible heat prior to reaching its contiguous thermocouple 30. The incoming air current sweeping between the somewhat warmer shield slats, carries off and returns to the test flame, most of the radiant heat that may have been dissipated in a direction counter to the air current flow in the passageway I2A. The accuracy of method on the part of my balanced thermal system is thereby kept inherently high, its error in determination has in actual p-ractice, been found correct to within about one tenth percent.

twill be obvious that the disclosed calorimeter can also be manipulated without the use of the described cooperating adjuncts; also that as'a simplification, it is not essential to resort to any intercooler, it being broadly within the scope of my invention to successively heat one and the same body of working fluid as applied to calorimeter purposes. Where a different temperature level prevails between the primary and the secondary combustion chambers, the slight discrepancy resulting from a change of specific heat in the working fluid, can readily be compensated for by correspondingly correcting the relative rates at which fuel is being fed to the respective test burners. In a like manner, other inherent instrument errors, such as a correction for the minor weight increase due to combustion products, may be allowed for by suitable calibration.

An outstanding advantage afforded by the described calorimeter instrumentalities, lies inthe ease with which the accuracy of its performance and correctness of adjustment can be checked.

lFor such purpose, standard gas is supplied to both pumps 6 IA and 6 Il?. and. the calorimeter put into operation. If said pumps do deliver exactly the same amount of gas per revolution, then by placing the idler wheel 5l in its one to one ratio position, identical rates of heat output should be furnished by the respective test burners. However, owing to certain irregularities and different inherent pumpz characteristics, the secondary burner will usually require a slightly larger supply of standard gas than does the primary burner. Definite compensation for such inherent inequalities can readily be made by shifting the idler wheel to a corrected base reference position where the desired initial thermal balance does actually exist between both chambers. My calorimeter may be calibrated to read directly in British thermal heat units as corrected for standard conditions of temperature, barometric pressure and air humidity.

Asa further modification of the same underlying principle, reference is had to Fig. 2. This disclosure is substantially similar to Fig. 1 as regards the calorimeter structure but provides for a different mode of control and measuring means.

. latter, are placed in the 200 series.

The secondary pump IIiB preferably handles standard reference gas and may be driven at constant speed by the motor |62 through the gearing E63 for delivery to the combustion chamber I IQB.` The primary pump ISIA then furnishes the unknown sample gas to the chamber IIGA and may be shaft driven from the motor |62 through two companion gear shift boxes 2 I2 and 2 I3, respectively .adapted to selectively modify the shaft speed. Either of these gear boxes may at will independently alter the speed ratio between such metering pumps but which pumps are operated at relatively fixed speeds in conformity with the anticipated heating values of the aforesaid test gases. The auxiliary gear box 2I3 may be utilized to -calibrate the index chart |59 in a manipulative manner that will presently be explained in detail. After having properly set the last named gear, the function of the adjusted' gear box 2 I 2 during .any given test run, is preferably confined to holding the respective gas deliveriesto the test burners I ISA and I I9B in fixed relationship.

Y In my Fig. 2 embodiment, certain modifications have also been introduced in the temperature responsive control devices, It will be observed that the secondary chamber lIFlB is here equipt with twoadditional thermocouples 250 and 2D! thatV are respectively located at thevoutlet and inlet regions of said chamber and arranged to through the slide Wire 238 sets up a voltage drop between its center tap C and any given position 0f the sliding contact 203, which drop is made directlyproportionate to the temperature rise imparted to the working iiuid while flowing through the chamber HEB. The purpose of such supplementary, series connected thermocouples is to supply said slide wire with the required actuating current in a proportionate relation to the temperature rise occurring in the secondary combustion chamber.

The several cooperating thermocouples |30, |3|, |32 and |33 are again connected in a manner such that when the temperature rise on the part of the working fluid flowing through the primary chamber ISA corresponds to that in the secondary chamber HDB, then no electromotive force will be eiective at the terminals |34 and |33. The lead terminal |38 is connected to the tap C of the slide wire 208 while the lead terminal |34 is connected in series with the main control relay |50 through the sliding potentiometer contact 289 which latter is shiftably mounted upon a suitable carrier. This carrier may be slidably actuated by the screw |54 that is rotated by the 4 reversible motor |52 through its gear |53; as in Fig. l, the rotation of this screw is determined by the direction of the unbalanced electrometive force received by the relay |50 and which prevailing carrier position is similarly recorded upon the chart |59.

The mode of operation of my Fig. 2 calorimeter may be traced as follows: As a iirst step, the instrument is calibrated with standard gas as previously explained in connection with the Fig. l disclosure, except that the o-ne to one pump speed ratio is secured by gear boxes 2 2 and 2 3. When the temperature rise in both'the primary and secondary chambers becomes substantially identical, then no electromotive force will be generated by the bank of interconnected thermocouples |33, i3 |32, and |33. Owing to the current ow that is set up through the slide wire 2il3 by the thermocouples 299 and 2M, a corresponding drop in voltage will occur between the tap point C of. the slide wire and the location of its sliding contact 299. Such small potential head serves to start up the relay |511 and thereby actuate the motor |52 to bring about a proportionate displacement oi the carrier until the desired degree of compensation has been attained. After correctly locating the reference position of the sliding contact, the middle of the index chart |59 is shifted to align with the stylus |58.

While manipulating the instrument for check purposes, the gear box 2|3 adjustably xes any required correction in the pump speed ratio, this box being arranged to definitely alter the speed of the pump I6 lA in relation to that of the pump |6|B so as to shift said stylus into a corrected reference position. Thereupon sample gas of unknown heating value is supplied to the primary metering pump 6 |A and any further pump speed adjustments required during a test run, may be confined to the gear shift box 2 l2.

When the complementary combustion chambers are operated without intercooler means,

liveries by which said last chamber is supplied 1n with a slightly larger amount of fuel suicient to maintain both component calorimeters in thermal balance. The pump delivery ratio is in part dependent upon the contemplated temperature range through which the instrument is intended to operate, to the end that the temperature rise in each of the respective combustion chambers may be kept substantially equalized. While the intercooler likewise recties the instrument readings,

such provision is more largely intended to maintain correct test determinations in case the rate of air iiow through the combustion chamber should Widely dier from that under which the calorimeter was calibrated.

In the Fig. 2 disclosure, the relative temperature leV-el of the working iiuid need not be kept equal in both chambers, but instead allows a definite difference to occur and this difference in temperature rise changes directly with the heating value of the tested sample gas when the flow rate of working iiuid is kept constant. The thermocouples of Fig. 2 automatically actuate the potentiometer in such fashion that the carrier movement is again made directly proportionate to a change in the heating value of the unknown gas.

In such application, the potentiometer is not used to measure the magnitude of temperature rise of the working fluid passing through one or both chambers, but to measure the difference between the rise of temperature in' one chamber relative to the temperature rise occurring in the other chamber. Furthermore, the potentiometer registers the difference of two such differences as a percentage of the total temperature rise in the secondary chamber i lB.

1f desired, an automatic potentiometer type of temperature recorder may likewise be used to register gas heating values, the only change being the center tapping of the slide wire. With this last arrangement, the thermocouple leads |34 and 266 would be connect-ed directly to the gaivanometer unit of the potentiometer recorder. It Will be obvious that the described calorimeters can also be manipulated without the use of the automatic registering adjuncts, and that if desired, manual control can be effected by using a galvanometer or some other current sensitive device in place of the automatic control relay.

My prior application, Serial No. 477,888, operates in a manner essentially similar to the present calorimeter devices except that an adjustable electric heater coil is connected to .a wattmeter or other power measuring instrument as a substitute for the present secondary chamber burner 29B in Fig. l or |2SB in Fig. 2. A heating coil and wattmeter combination of this kind is shown in Fig. 3 and respectively designated by the numerals 30|] and 38|. Such combination may be used as a measurable reference basis against which to compare and balance the rate of heat output being delivered by the test flame in the primary chamber. The described reheating of a gaseous working fluid is believed to differ broadly from and to constitute a novel contribu- The same tion over the prior calorimeter art. cooperative results can also be achieved when reversing the described heating steps by interchanging the primary test burner with the secondary test burner or its equivalent heating coil.

It is though that the foregoing rather explicit disclosure when taken in connection with the accompanying drawings, clearly teaches how to fabricate and manipulate my improved calorimeter. Other inherent advantages are thought to be made apparent to those skilled in the art, it being understood that I reserve the right to substantially modify the structural elements of my illustrative embodiments to meet commercial requirements, all without departing from the spirit and scope of my invention heretofore described and more particularly pointed out in the appended claims.

I claim:

1. A calorimeter ofthe multiple type comprising a pair of complementary heating chambers each provided with an intake port and a dischargeport, conduit means operatively interconnecting the respective chambers in series, means establishing a flow of gaseous Working fluid into and through the respective chambers, test name means located Within one such chamber and serving to initiate a temperature rise in the working fluid flowing therethrough, and measurable supplementary heating means located within the other chamber and serving to subject the same working fluid to a quantitatively measured heating effect suflicient to raise the temperature of said Working fluid in a definite proportionate relationship to the aforesaid initial temperature rise.

2. A calorimeter comprising a pair of complementary heating chambers each provided with an intake and a discharge port, conduit means operatively interconnecting the respective chambers in series, means establishing a flow of gaseous working fluid through the respective chambers, test burner means located within one such chamber and serving to initiate a limited degree of 'temperature rise in the Working fluid owing therethrough, measurable supplementary heating means located Within the other chamber and serving to subject the same Working fluid to a quantitatively measured heating effect and thereby raise the temperature of said fluid a substantially like degree, and temperature responsive means for determining when a like degree of temperature rise has been attained in each of the repective chambers.

3. A calorimeter of the multiple upright type comprising a pair of complementary tubular combustion chambers that are vertically disposed and each pro-vided with an intake port at the bottom end region thereof and a discharge port, at thev upper end region thereof, an updraft test burner housed within Veach such chamber, conduit means operatively interconnecting the discharge port of one such chamber with the intake port of the other chamber, tubular cooler means disposed in the conduit means and between the respective conduit ends.V and separate temperature responsive means located in each of said chambers. c

4. A calorimeter 'of the multiple upright type comprising a pair of complementary tubular combustion chambers that are vertically disposed and each provided with an intake port at the bottom end region thereof anda discharge port at the upper end region thereof,` an updraft test burner housed Within one such chamber, conduit means operatively interconnecting the discharge port of onesuch chamber with the intake portof the other chamber, a heat exchanger including tubular intercooler means and a. surrounding shell to constitute complementary heat exchanger compartments of which one such compartment is inbuilt into the aforesaid conduit as a component thereof, feed duct means for the other heat exchanger compartment, and a passageway interconnecting the last named compartment With the remaining intake port.

5. A calorimeter comprising a chamber of the tubular type of which one end region is provided with an intake port and the opposite end region is provided With a discharge port, a test burner mounted interiorly of said chamber, intercooler means disposed exteriorly of the chamber confines and comprising complementary compartments of which one such compartment communicates with the intake part and the other compartment communicate with the discharge port, means supplying fresh air to the intake port through its interconnected compartment, said air being thereupon heated by the burner and conveyed Onward through said discharge port and the other intercooler compartment in a heat exchanging relationship With the fresh air being supplied to the aforesaid one compartment.

6. A calorimeter comprising a pair of component chambers each provided with an intake port and a discharge port, a heat exchanger comprising complementary compartments, conduit means 'interconnecting the discharge port of one such chamber with the intake port of the other chamber and which conduit delivers through one of the heat exchanger compartments, passageway means operatively connecting the companion heat exchange compartment for delivery to the remaining intake port, means supplying a continuous flow of working iiuid to and through said companion compartment, a test burner disposed Within the confines of the aforesaid one chamber, said working fluid being heated by said burner and conveyed onwardly into and through said conduit and serving to preheat the incoming Working fluid supplied to said companion compartment.

7. A calorimeter of the multiple'type comprising a pair of chambers that are cooperatively interconnected by conduit means, a test burner disposed in one such chamber and fed with a combustible of unknown heating value, measurable supplementary heating means disposed in the other chamber, and means delivering gaseous Working fluid into and successively through both chambers, said test burner serving to heat the Working fluid at a certain rate of input and the supplementary `heating means subjecting the same fluid to a measured heating effect that shall be commensurate with the aforesaid certain input rate.

8. A calorimeter of the multiple type comprising complementary chambers that are cooperatively interconnected by conduit means, a test burner disposed in one such chamber and fed with a combustible of unknown heating value, measurable supplementary heating means disposed in the other chamber, means delivering gaseous working fluid successively through both heating effect that is commensurate with the aforesaid certain input rate, and temperature responsive means for each such chamber.

9. A calorimeter of the multiple type comprising complementary chambers that are cooperatively interconnected by conduit means, a test burner disposed in one such chamber and fed with a combustible of unknown heating value, measurable supplementary heating means disposed in the other chamber, means delivering gaseous working uid successively through both chambers, said test burner serving to heat the working iiuid at a certain input rate and the supplementary heating means serving to impart to the same working fluid a measured heating effect that is substantially balanced with respect to the aforesaid certain input rate, and temperature responsive means for each such chamber, said means being of the differential type arranged to make manifest when a balanced temperature rise has been achieved.

l0. A calorimeter of the multiple type comprising complementary combustion chambers that are cooperatively interconnected by conduit means, cooler means disposed in the conduit means and between the respective conduit ends, a test burner arranged in one such chamber and fed with a combustible of unknown heating value, a supplementary test burner arranged in the other chamber and fed with standardized reference gas, and means delivering gaseous working fluid containing air successively through both chambers, one such burner serving to initially heat the working fluid prior to reaching the cooler means and the other burner serving to reheat the same working fluid subsequent to being cooled.

1l. A calorimeter comprising a pair'of conduit interconnected combustion chambers that are respectively provided with an inlet port admitting a common stream of gaseous working fluid containing air for delivery through both such chambers, a primary test burner operatively housed in one such chamber, primary metering means delivering a combustible of unknown heating value to said test burner, a secondary test burner operatively housed in the other combustion chamber, secondary metering means delivering a combustible of known heating value to the last named burner, and control means serving to alter the proportionate delivery between the primary and the secondary metering means.

12. A calorimeter comprising complementary communicating combustion chambers each provided with an inlet port respectively admitting therethrough a common gaseous working iiuid containing air, a separate test burner operatively housed within each such chamber, a rotatable metering pumpdelivering a combustible of unknown heating value to one such test burner, another rotatable metering pump delivering a combustible of known heating value to the other burner, and drive means for ac tuating th'e metering pumps in unison, said drive including shiftable control means serving to selectively alter the speed ratio between said pumps.

13. A calorimeter comprising complementary communicating combustion chambers each provided with an inlet port which respective ports successively admit therethrough a common gaseous working fluid containing air, a separate test burner operatively housed withinl each such chamber, a rotatable metering pump delivering a combustible of unknown heating value to one aoearso such test burner, another rotatable metering pump delivering a combustible of known heating value to the other burner, an adjustable transmission mechanism including a pair of differential drums that are respectively connected to 5 said metering pumps, said mechanism further including shiftable idler means operatively interposed between said drums, motive means arranged to directly drive one of said drums and to indirectly drive the companion drum through said idler means, and adjusting means for selectively shifting the position of the idler means.

14. A calorimeter comprising complementary communicating combustion chambers each provided with an inlet port which respective ports successively admit therethrough a common gaseous working iiuid containing air, a separate test burner operatively housed within each such chamber, a rotatable metering pump delivering a combustible of unknown heating value to one such test burner, a second rotatable metering pump delivering a combustible of known heating value to the other burner, drive means for actuating the metering pumps in unison, said drive including shiftable control means serving to selectively alter the speed ratio between said pumps, stylographic pointer means arranged to shift in synchronism with the control means, and a chart serving to record the prevailing pointer position. 15. A calorimeter comprising complementary communicating combustion chambers each provided with an inlet port which respective ports successively admit therethrough a common working fluid containing air, a separate test burner operatively housed within each such chamber, a metering pump delivering a combustible of unknown heating value to one such test burner, a second metering pump delivering a combustible of known heating value to the other burner, adjustable transmission means driving the metering pumps in unison, said means including shiitable control means serving to selectively alter the delivery ratio between said pumps and thereby correspondingly change the rate of heat input imparted to the working iiuid by the respective test burners, an electrical temperature responsive device for each such chamber, said devices being wired in opposition for diiferential action, relay means wired in a common circuit with the aforesaid devices, and a remote control motor commanded by said reiay and serving to adjustably shift the aforesaid control means in response to current iiow in said circuit.

16. A calorimeter comprising a pair of conduit interconnected chambers respectively provided with an inlet port admitting a common stream of gaseous working iiuid containing air for delivery in series through both such chambers, a test burner operatively housed in one such chamber, and positively driven draft producing means serving to intensify the natural flow of Working iiuid through said chambers.

i7. A calorimeter comprising a pair of conduit interconnected chambers respectively provided with an inlet port admitting therethrough a stream of gaseous working iiuid containing air for delivery in series through both such chambers, a test burner operatively housed in one such chamber, and feed pipe means delivering a com- 7o bustible to the burner, said means including a preheater loop section disposed within the aforesaid interconnecting ccnduit subjected to heat irom the burner iiame.

18. A calorimeter of the multiple type comprising a pair of complementary heating chambers each provided with anl intake and a discharge port, conduit means operatively interconnecting the respective chambers in series, means establishing a flow of gaseous working fluid through the respective chambers, a test burner located within one such chamber and serving to initiate a temperature rise in the working fluid flowing therethrough, measurable supplementary heating means located in the other chamber and serving to subject the same working fluid to a quantitatively measured heating effect that raises the temperature of said working fluid in a proportionate relationship to the aforesaid initial temperature rise, temperature responsive means for each of said heating chambers, and actuated recorder means placed under the control of the respective temperature responsive means.

19. A calorimeter comprising a combustion chamber provided with an inlet port admitting a stream of gaseous working fluid thereto, a test burner operatively housed within said chamber, means responsive to the incoming temperature of the working fluid, and an antiradiaticn shield interposed between said thermometer means and the burner, said shield comprising a plurality of angle shaped slats spacedly stacked in superimposed relation and placed crosswise of the working fluid stream.

20. A calorimeter comprising a pair of complementary combustion chambers, each including upright tubular jacket means, a lining for each such combustion chamber that is interiorly spaced from the jacket thereof and cooperatively disposed to constitute an annular hermetically sealed vacuum chamber therebetween, a test flame housed within the lining of each such combustion chamber and which respective flames are protectively insulated by the vacuum chamber thereof, and conduit means serving to interconnect the top region of one such lining with the bottom region of the other lining.

21. A calorimeter comprising a longitudinally chambered jacket member, a tubular draft casing of which one end is closed and having crown delivery ports through said closed end region together with a draft intake port located at the opposite end thereof and which casing is telescopically entered into said jacket in a circumferentially spaced relationship, a test burner housed within said casing with its flame disposed intermediate the respective crown and draft ports thereof, means supplying a combustible to the burner, and means simultaneously supplying air to said draft port and also between the aforesaid circumferential spacing, said air flowing in a common direction toward said crown port and the products of combustion being continued onward in the aforesaid common direction.

22. A calorimeter comprising a combustion chamber including a tubular jacket member provided with a crown plate and an outlet tube depending from said plate, a test burner operatively housed within one end region of said jacket, and a tubular mixing box suspended from the free end of said outlet tube and located within the opposite jacket end region in a longitudinally spaced relation to the test burner, said box including an inflowing turbulence port that injects radially inward toward the box axis and having an axially disposed discharge port that delivers away from the test burner and through said outlet tube.

23. A calorimeter comprising a combustion 10 chamber including an upright tubular jacket member, a crown plate for the upper end of said jacket, an outlet tube depending from said plate,

a mixing box including inflowing turbulence ports and which box is carried by and delivers through said tube, a test burner mounted within the jacket connes beneath said box, and a temperature responsive device located within said tube.

24. A calorimeter of the multiple type comprising a pair of complementary heating chambers each provided with an intake and a discharge port, conduit means operatively interconnecting the respective chambers in series, means establishing a stream of gaseous working fluid through the respective chambers, a test burner located within one such chamber and serving to initiate a temperature rise in the working fluid flowing therethrough, measurable supplementary heating means located in the other chamber and serving to subject the same working fluid to a quantitatively measured heating effect suflicient to raise the temperature of said working fluid in a proportionate relationship to the aforesaid initial temperature rise, a pair of series connected thermocouples located respectively in advance of and behind the test flame, another pair of series connected thermocouples located respectively in advance of and behind said supplemental heating means, said pairs of thermocouples being respectively placed in the path of the stream of working fluid and made responsive to the rise in temperature thereof, and lead means interconnecting the aforesaid pairs of thermocouples in opposed relationship for differential action.

25. A calorimeter of the multiple type comprising a pair of complementary heating chambers each provided with an intake and a discharge port, conduit means operatively interconnecting the respective chambers in series, means establishing a current of gaseous working fluid through the respective chambers, separate heating means for each such chamber serving to raise the temperature of the working fluid flowing therethrough, temperature responsive means including a pair of series connected thermocouples respectively located in advance of and behind one of the aforesaid heating means and made responsive to the temperature rise occurring in said current, potentiometer slide wire means, and lead means operatively interconnecting such thermocouples with the respective end regions of said slide wire.

RAFAEL W. KEITH.

CERTIFICATE OF CORRECTION.

Patent No. 2,026,180. December 31, 19E

RAFAEL W. KEITH.

It is hereby certified that error appears in the vprinted specification oi the above numbered patent requiring correction as follows: Page 8, second column, line l5-'74, claim 17, strike out the words "subjected to heat from the burner flamev; and that the said Letters Patent should be read with thi; correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 3rd day of March, A. D. 1936.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

